Improved ferroelectric performance of La:Hf0.5Zr0.5O2 thin films

This work was supported by Russian Science Foundation (Project. No 18-19-00527)

The restricted two-body problem in constant curvature spaces

We perform the bifurcation analysis of the Kepler problem on $S^3$ and $L^3$. An analogue of the Delaunay variables is introduced. We investigate the motion of a point mass in the field of the Newtonian center moving along a geodesic on $S^2$ and $L^2$ (the restricted two-body problem). When the curvature is small, the pericenter shift is computed using the perturbation theory. We also present the results of the numerical analysis based on the analogy with the motion of rigid body.Comment: 29 pages, 7 figure

Non-linear stability in photogravitational non-planar restricted three body problem with oblate smaller primary

We have discussed non-linear stability in photogravitational non-planar restricted three body problem with oblate smaller primary. By photogravitational we mean that both primaries are radiating. We normalised the Hamiltonian using Lie transform as in Coppola and Rand (1989). We transformed the system into Birkhoff's normal form. Lie transforms reduce the system to an equivalent simpler system which is immediately solvable. Applying Arnold's theorem, we have found non-linear stability criteria. We conclude that $L_6$ is stable. We plotted graphs for $(\omega_1, D_2).$ They are rectangular hyperbola.Comment: Accepted for publication in Astrophysics & Space Scienc

Баланс интересов авторов произведений и широкой общественности

The authors investigate into the rules contained in the international treaties, Russian existing laws and judicial routine related to exclusiveness of authors’ rights. The character of social changes in the digital era were specified. Several types of legal relations remain traditional, however in today’s information society has to revise existing laws in which authors rights dominate over information user interests. At the same time, the authors re underprotected from piracy. Legislators have to prioritize in the first place who and from whom must be protected in the information society: the authros from pirates, intellectual property from plagiarism, or the users from actualaccessible information. Secondly, the rights of new knowledge have to be managed and efficient ways to righ t-ful transfer of accumulated knowledge to users have to be found. Implementation of information technologies into libraries and access to digital information resources change radically the quality of library services. The authors challenged themselves with attracting attention to the problems of information society in Russia.Авторы статьи исследуют нормы международных договоров, российские правовые реалии, судебную практику в отношении исключительности прав авторов произведений. В ходе исследования выявлен характер социальных изменений, происходящих в эпоху цифровых технологий. Некоторые виды правоотношений продолжают существовать в прежней юридической форме, однако для современного этапа развития информационного общества следует пересмотреть отдельные действующие нормы права, сохраняющие доминирование прав автора произведения над интересами потребителей информации. Вместе с тем авторы произведений слабо защищены от пиратских действий. Возникают, во-первых, необходимость законодателю определиться в приоритетах: кого и от кого следует защищать в информационном обществе – авторов от пиратства, интеллектуальную собственность от плагиата или читателей от актуальной доступной информации; во-вторых, потребность управления правами самих создателей новых знаний и поиск оптимальных путей правомерной передачи накопленных знаний пользователям. Внедрение информационных технологий в работу библиотек кардинально меняет качество библиотечного обслуживания за счёт предоставления доступа к информационным ресурсам в электронной форме. Авторы статьи ставили перед собой цель привлечь внимание к проблемам развития информационного общества в России

Violent solar events of October-November 2003 as recorded by IZMIRAN radio observations

The extreme solar activity of October-November 2003 was recorded at IZMIRAN with digital radiospectrographs at 25-270 MHz and fixed-frequency radiometers at 169, 204 and 3000 MHz. An outstanding metre-wavelength noise storm took place during the fist passage of the grandiose evolving active complex across the disc which testifies to permanent electron acceleration over the complex with energy of up to tens of kiloelectronvolts. Against this background, intense metric and microwave radio bursts were recorded in association with several outstanding flare and huge coronal mass ejection (CME) events. The dynamic spectra of these events display multiband and sometimes fine-structure type II bursts, initiated by coronal shocks, and various continuum emissions. In some cases, a corresponding microwave burst at 3000 MHz includes not only an impulsive component coinciding with a flare maximum but also a predominating delayed long-duration component with a smooth time profile. The latter component is thought to be linked with a post-eruptive energy release and particle acceleration when the magnetic field, strongly disturbed by a CME, relaxes to a new quasi-equilibrium configuration via reconnection in high coronal levels

Identification of the nature of traps involved in the field cycling of Hf₀.₅Zr₀.₅O₂-based ferroelectric thin films

The discovery of ferroelectricity in hafnium oxide has revived the interest in ferroelectric memories as a viable option for low power non-volatile memories. However, due to the high coercive field of ferroelectric hafnium oxide, instabilities in the field cycling process are commonly observed and explained by the defect movement, defect generation and field induced phase transitions. In this work, the optical and transport experiments are combined with ab-initio simulations and transport modeling to validate that the defects which act as charge traps in ferroelectric active layers are oxygen vacancies. A new oxygen vacancy generation leads to a fast growth of leakage currents and a consequent degradation of the ferroelectric response in Hf₀.₅Zr₀.₅O₂ films. Two possible pathways of the Hf₀.₅Zr₀.₅O₂ ferroelectric property degradation are discussed

Integrable Euler top and nonholonomic Chaplygin ball

We discuss the Poisson structures, Lax matrices, $r$-matrices, bi-hamiltonian structures, the variables of separation and other attributes of the modern theory of dynamical systems in application to the integrable Euler top and to the nonholonomic Chaplygin ball.Comment: 25 pages, LaTeX with AMS fonts, final versio

Leakage Currents Mechanism in Thin Films of Ferroelectric Hf 0.5 Zr 0.5 O 2

We study the charge transport mechanism in ferroelectric Hf 0.5 Zr 0.5 O 2 thin films. Transport properties of the leakage currents in Hf 0.5 Zr 0.5 O 2 are described by phonon-assisted tunneling between traps. Comparison with transport properties of amorphous Hf 0.5 Zr 0.5 O 2 demonstrates that the transport mechanism does not depend on the crystal structure. The thermal trap energy of 1.25 eV and optical trap energy of 2.5 eV in Hf 0.5 Zr 0.5 O 2 were determined based on comparison of experimentally measured data on transport with simulations within phonon-assisted tunneling between traps in dielectric films. We found that the trap density in ferroelectric Hf 0.5 Zr 0.5 O 2 is slightly less that one in amorphous Hf 0.5 Zr 0.5 O 2 . A hypothesis that oxygen vacancies are responsible for the charge transport in Hf 0.5 Zr 0.5 O 2 is confirmed by electronic structure ab initio simulation

U-shaped type II solar radio bursts associated with the 1980 March 28 flare

Observations of the 1980 March 28, 2B flare in optical, radio microwave and metric and X-ray wavelengths are presented. In the dynamic radio spectrum, unusual and rare U-shaped type II radio bursts associated with this flare have been observed. The normal type II bursts display negative frequency drift, due to the flare-triggered shock wave travelling outwards in the solar corona. But in this case the type II emission first showed the usual negative frequency drift, and then after reaching a plateau level, showed a positive drift, thus giving the shape of an inverted "U". The authors propose a model for this type II emission.We suggest that the shock wave generated by the flare or the flare spray propagates through sucting and repeated reflections, which takes place within a large scale coronal loop or an arcade of loops, thus resulting in reverse frequency drift in type II emission